M, MII:Professional tape formats from Panasonic. The M format was based on VHS technology, and was introduced at about the same
time as Beta (in the mid-1980's). The MII format was introduced a few years later to compete with Beta SP. MII uses a different sized cassette.More info: M, MII

Mix (1):A video transition in which one shot gradually fades into the next. AKA crossfade or dissolve.More info: The mix transition

Mixer:A device which accepts multiple signal inputs (video or audio), processes them, and provides one or more outputs. The outputs are "mixes" of the input sources.More info: Audio mixers, Vision mixers